B vitamins are a group of eight water-soluble vitamins (B1, B2, B3, B5, B6, B7, B9 and B12) that the body needs to release energy from food, for the functioning of the nervous system and for the formation of red blood cells [1]. Because the body does not store them, with the exception of vitamin B12, they need to be taken in regularly [2]. In this article, you will learn what the individual B vitamins do, which foods contain them, what their active forms are and when it makes sense to reach for a B-complex.
What will you learn in this article?
- What do B vitamins do?
- B-complex benefits: what each B vitamin does in the body
- Where is vitamin B found? An overview of B1 to B12
- Methylfolate and methylcobalamin: what are the active forms of B vitamins?
- When to take a B-complex and how to choose one
- Key takeaways
What Do B Vitamins Do?
B vitamins act in the body as coenzymes, helper molecules without which many enzymes could not work. They are involved in converting nutrients into energy, in forming and repairing DNA, in methylation and in producing neurotransmitters [1].
Each B vitamin has a different role, but in metabolism they often work together. For example, folate (B9), vitamin B12 and vitamin B6 together contribute to normal homocysteine metabolism [5]. That is why B vitamins are often supplemented together, in the form of a B-complex.
B-Complex Benefits: What Each B Vitamin Does in the Body
According to the authorised EU health claims, B vitamins contribute in particular to [5]:
- normal energy-yielding metabolism (B1, B2, B3, B5, B6, B7, B12),
- normal functioning of the nervous system (B1, B2, B3, B6, B7, B12),
- normal psychological function (B1, B3, B6, B7, B9, B12),
- the reduction of tiredness and fatigue (B2, B3, B5, B6, B9, B12),
- normal red blood cell formation (B6, B12) and normal blood formation (B9),
- the normal function of the immune system (B6, B9, B12),
- the maintenance of normal skin (B2, B3, B7) and hair (B7).
Where Is Vitamin B Found? An Overview of B1 to B12
Each of the eight B vitamins has different main food sources. The overview shows what each vitamin contributes to and where to find it.
Vitamin |
Contributes to (selection) |
Food sources |
B1 (thiamine) |
the normal function of the heart and nervous system, and normal energy-yielding metabolism |
pork, fish, whole grains, legumes, yeast |
B2 (riboflavin) |
the maintenance of normal skin and vision, and normal iron metabolism |
milk and dairy products, eggs, meat, offal, whole grains |
B3 (niacin) |
the maintenance of normal skin and mucous membranes, and normal functioning of the nervous system |
meat, poultry, fish, grains, legumes |
B5 (pantothenic acid) |
normal synthesis and metabolism of steroid hormones, vitamin D and some neurotransmitters, and normal mental performance |
liver, meat, milk, whole-grain foods, legumes, yeast |
B6 (pyridoxine) |
normal psychological function, normal red blood cell formation, and the regulation of hormonal activity |
fish, poultry, liver, potatoes, legumes, some fruits |
B7 (biotin) |
the maintenance of normal hair and skin, and normal macronutrient metabolism |
egg yolk, liver, nuts, legumes |
B9 (folate) |
maternal tissue growth during pregnancy, normal blood formation, and the process of cell division |
leafy vegetables, legumes, liver, eggs, whole grains |
B12 (cobalamin) |
normal red blood cell formation, normal functioning of the nervous system, and the process of cell division |
meat, fish, eggs, dairy products, fortified foods |
Vitamin B12 is found naturally mainly in foods of animal origin. However, it can also be obtained from foods fortified with it or from dietary supplements [2]. With the exception of vitamin B12, whose stores in the liver can last for several years, the body does not store B vitamins, so they need to be taken in regularly [2].
We describe how it shows when B vitamins are lacking, who is most at risk of deficiency and how to check it in a separate article: B Vitamin Deficiency: Symptoms, Causes and Best Sources.
Methylfolate and Methylcobalamin: What Are the Active Forms of B Vitamins?
Folic acid, the common synthetic form of vitamin B9, must first be converted in the body into the active form 5-methyltetrahydrofolate (methylfolate). Methylfolate is available to the body directly, without this conversion, and is used in dietary supplements as an alternative to folic acid [3].
Part of the population has a variant of the MTHFR gene that can reduce how efficiently folate is converted into its active form [3]. Like methylfolate, methylcobalamin, one of the active forms of vitamin B12, is also used in supplements.
The form of folate matters especially when planning a pregnancy and during pregnancy, when folate contributes to maternal tissue growth [5]. You can learn more about folate in the article Folate – the health gem you might be missing.
When to Take a B-Complex and How to Choose One
A varied diet is the foundation. A B-complex can make sense when your need for B vitamins cannot be covered by your usual diet. Because B vitamins build on each other in metabolism, it tends to be more practical to supplement them together rather than individually [1].
B-complex or multivitamin?
A B-complex contains only B vitamins. A multivitamin also contains other vitamins and minerals. If you want to cover a wider range of nutrients, a multivitamin with enough B vitamins is more practical. If you specifically need only B vitamins, a B-complex is enough. However, do not take both at the same time without checking the total doses.
When during the day should you take a B-complex?
Many people take a B-complex in the morning with food, because it fits easily into a daily routine and supplements are usually better tolerated with a meal. What matters more than the time of day, however, is taking it regularly.
What to look for when choosing one
- All eight B vitamins in reasonable amounts, because they build on each other in metabolism [1].
- The form of folate and B12, that is, whether the supplement contains active forms such as methylfolate or methylcobalamin [3].
- The dose of vitamin B6. Choose a supplement with a reasonable dose of B6 and do not exceed the recommended dosage [4].
- Where the vitamins come from. For example, the Daily F20 Complex multivitamin contains B vitamins from sprouted buckwheat.
If you take a B-complex together with other supplements, keep an eye on your total intake. Vitamin B6 is also found, for example, in our magnesium with zinc and vitamin B6. We explain why these nutrients are combined in the article Magnesium, Zinc and Vitamin B6: Why This Combination Works and When to Take It.
Key Takeaways
There are eight B vitamins: B1, B2, B3, B5, B6, B7, B9 and B12 act as coenzymes in the body and build on each other in metabolism.
They contribute to energy and the nervous system: they are involved in normal energy-yielding metabolism, the functioning of the nervous system, psychological function and red blood cell formation.
The body does not store them: with the exception of vitamin B12, they need to be taken in regularly from the diet.
A varied diet is the best source: meat, fish, eggs, dairy products, whole grains, legumes and leafy vegetables.
Methylfolate is the active form of folate: the body does not need to convert it further, which is why it is used in dietary supplements as an alternative to folic acid.
With a B-complex, form and dose matter: check the form of folate and B12, and do not exceed the recommended dose of vitamin B6.
Sources
[1] Kennedy DO. B Vitamins and the Brain: Mechanisms, Dose and Efficacy – A Review. Nutrients. 2016;8(2):68. doi:10.3390/nu8020068. https://doi.org/10.3390/nu8020068
[2] National Institutes of Health, Office of Dietary Supplements. Vitamin B12: Fact Sheet for Health Professionals. https://ods.od.nih.gov/factsheets/VitaminB12-HealthProfessional/
[3] National Institutes of Health, Office of Dietary Supplements. Folate: Fact Sheet for Health Professionals. https://ods.od.nih.gov/factsheets/Folate-HealthProfessional/
[4] National Institutes of Health, Office of Dietary Supplements. Vitamin B6: Fact Sheet for Health Professionals. https://ods.od.nih.gov/factsheets/VitaminB6-HealthProfessional/
[5] Commission Regulation (EU) No 432/2012 establishing a list of permitted health claims made on foods. https://eur-lex.europa.eu/eli/reg/2012/432/oj
